Polycarbonate

POLYCARBONATE

Polycarbonates, known by the trademarked names Lexan, Makrolon, and others, are a particular group of thermoplastic polymers. They are easily worked, moulded, and thermoformed. Because of these properties, polycarbonates find many applications. Polycarbonate is the first commercially useful thermoplastic material which incorporates the carbonate radical as an integral part of the main polymer chain.

Properties

Polycarbonate derived from BPA is a very durable material. Although it has high impact-resistance. The characteristics of polycarbonate are quite like those of polymethyl methacrylate (PMMA, acrylic), but polycarbonate is stronger, usable in a wider temperature range. This polymer is highly transparent to visible light and has better light transmission characteristics than many kinds of glass. Unlike most thermoplastics, polycarbonate can undergo large plastic deformations without cracking or breaking. As a result, it can be processed and formed at room temperature using sheet metal techniques, such as forming bends on a brake. Even for sharp angle bends with a tight radius, no heating is generally necessary. This makes it valuable in prototyping applications where transparent or electrically non-conductive parts are needed, which cannot be made from sheet metal. Low water absorption high heat resistance, thermal stability and good electrical properties and very high impact strength are among the many desirable properties that Polycarbonates possess.

Applications

Electronic components - Being a good electrical insulator and having heat and flame resistant properties, it is used in myriad products associated with electrical and telecommunications hardware. It is used as dielectric in high stability capacitorsConstruction materials - The second largest consumer of polycarbonates is the construction industry, e.g. for domelights, flat or curved glazing, and sound walls.Data storage - A major application of polycarbonate is the production of compact discs, DVDs, and Blu-ray Discs. The blanks are produced by injection molding.Typical products of sheet/film production include applications in advertisement (signs, displays, poster protection).Automotive, aircraft, and security components - In the automotive industry, injection moulded polycarbonate can produce very smooth surfaces that make it well suited for direct (without the need for a basecoat) metalised parts such as decorative bezels and optical reflectors. Its uniform mould shrinkage results in parts with greater accuracy than those made of polypropylene. However, due to its susceptibility to environmental stress cracking, its use is limited to low stress applications. It can be laminated to make bullet-proof "glass", although "bullet-resistant" is more accurate for the thinner windows, such as are used in bullet-resistant windows in automobiles. The thicker barriers of transparent plastic used in teller's windows and barriers in banks, are also polycarbonate. So called "theft-proof" large plastic packaging for smaller items, which cannot be opened by hand, is uniformly made from polycarbonate. The cockpit canopy of the F-22 Raptor jet fighter is made from a piece of high optical quality polycarbonate, and is the largest piece of its type formed in the worldNiche applications - Many kinds of lenses are manufactured from polycarbonate, including automotive headlamp lenses, lighting lenses, sunglass/eyeglass, lenses, and safety glasses. Other miscellaneous items: MP3/Digital audio player cases, Ocarinas, computer cases, riot shields, visors, instrument panels. Many toys and hobby items are made from polycarbonate parts, e.g. fins, gyro mounts, and flybar locks for use with radio-controlled helicopters.The fact that polycarbonates has exceptionally high impact strength suggest its use in applications where toughness is a requisite, such as housings for business machines, communication equipment, automotive, aircraft and security components.